package com.example.demo.NiuKe.v09;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str;
        while ((str= br.readLine())!=null){
            Map<String,String> map = new HashMap<>();
            int count =0;
            for (int i = 0;i<str.length();i++){
                String s = str.charAt(i)+"";
                if(!map.containsKey(s)){
                    count++;
                    map.put(s,null);
                }
            }
            System.out.println(count);
        }
    }
}
